Agilent Technologies 6890 Series Service Manual page 208

310 Flame Ionization Detector (FID)
Theory of operation
The FID uses a flame produced by the combustion of hydrogen and air. Few
ions are formed until an organic compound elutes into the flame. Then a large
increase in ions occurs. A collector with a polarizing voltage is applied near
the flame, attracting the ions and producing a current, which is proportional
to the amount of sample present in the flame.
Pneumatic lines
Detector tower
Ignitor cable
Figure 310-1
EPC detector
The EPC FID has three pneumatic supply lines for air, hydrogen and makeup
gas. Each line has a filter frit, a proportional valve controlled by a pressure
Jun 2001
The Flame Ionization Detector (FID)
Detectors
Agilent 6890 Gas Chromatograph Service Manual
Electrometer
Heater/sensor cable
Electrometer ribbon cable
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